The association of premorbid psychological factors (PPF) -- stress, personality, social environment -- and cancer incidence and mortality has often been reported as present, and occasionally as absent. A theoretical examinaton of the issues in this field was carried out, pointing to possible flaws in the design of most studies, with resulting questions about their conclusions. It further emphasized the need for prospective work. In the present two prospective studies, each member of a cohort, presumed initially without cancer, will have produced PPF data on entry (1930's to 1960's, and 1958, respectively). Follow-up of cancer death and incidence is in progress and PPF will be related to them. 17-year follow-up of the St. Luke's cohort has yielded the following relationship: Those whose highest score on the MMPI was the depression scale score had a relative risk greater than 2 compared with others in the cohort. The hypothesis that anxiety and depression are related to cancer was not upheld. The theory of the relationship of PPF and cancer is being further pursued in the areas of immune function, life stress, and competing risk.